Self-opening die-head



March 27, 1934.

A. F. BREITENSTEIN SELF OPENING DIE HEAD Filed April 27, 1933 2 sheets-sheet 1 March 27, 1934 A. F. BREITENSTEIN 1,952,743

SELF OPENING DIE HEAD Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE 1,952,743 x SELF-oprime. D1E-HEAD Application April 27, 1933, Serial No. 668,200

4 Claims.

'I'his invention relates to an improvement in self-opening die-heads and relates in particular to an improvement in that class of self-opening die-heads in which the chasers or cutters are mounted in a Chaser-carrying member which is mounted, in turn, with capacity for independent reciprocating movement in a mounting-member designed to be secured in the turret or other appropriate feature of a machine. This class of self-opening die-heads are characterized by their capacity for being tripped by a relative forward draft exerted upon the chasers by the work, and are in some instances referred to as pull-olf die-heads.

The present invention constitutes an improvement over the die-head shown in United States vPatent No. 1,643,832, dated September 27, 1927, and applied for in my name and that of E. A. Barteit.

One of the objects of the present invention is to provide a convenient and reliable self-opening die-head of the class described, constructed with particular reference to sensitiveness of its tripping mechanism, whereby threads of fine pitch and delicate form may be rapidly and accurately cut in hard or soft material without danger of stripping the threads from such material.

Another object is to provide a self-opening diehead of the class described which is capable of withstanding continued and hard usage without undue wear of its locking and tripping features.

A further object is to provide an accurate, reliable and effective self-opening die-head which may be produced at a relatively-low cost for manufacture.

Other objects and advantages will appear to those skilled in the art from the following, taken in conjunction with the accompanying drawings and the appended claims.

In the accompanying drawings:

Fig. 1 is a view in side elevation of one form which a self-opening die-head embodying the present invention may assume;

Fig. 2 is a view thereof in front-end elevation but on a larger scale;

Fig. 3 is a central, longitudinal, sectional view taken on the line 3-3 of Fig. 2 and showing the parts of the die-head in the positions which they assume when the chasers are in their cutting positions;

Fig. 4 is a view corresponding to Fig. 3 but showing the Chaser-carrying member moved forwardly relative to the mounting-member to retract the locking member, which latter is shown in the position which it assumes at the instant a mounting-member 20, a Chaser-carrying memying an internal cylindrical bearing-surface 29 of its disengagement from its complementary locking-abutment;

Fig. 5 is a central, longitudinal, sectional view corresponding to Figs. 3 and 4, save that the parts are shown in the positions which they assume 00 when the die-head has been tripped and the chasers retracted;

Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 1;

Fig. 7 is a fragmentary view in longitudinal e5 section taken on the line 7-7 of Fig. 2;

Fig. 8 is a similar view, taken on the line 8-8 of Fig. 2;

Fig. 9 is a similar view, taken on the line 9-9 of Fig. 2; ,70

Fig. 10 is a similar view, taken on the line 10-10 of Fig. 2;

Fig. 11 is a brokenl view in side elevation of the mounting-member;

Fig. 12 is a broken underside view thereof; and

Fig. 13 is a perspective View of the lockingmember detached.

The particular embodiment of the present invention herein chosen for illustration includes I8() ber 21, a sleeve-like Chaser-operating member 22, a segmental locking-member 23 and an adjusting-ring 24.

The mounting-member 20 is of tubular form and includes a hollow forwardly-projecting bearing-extension 25, a substantially-central radially-extending flange 26 and a rearwardly-projecting hollow shank 27 virtually forming a continuation of the forwardly-projecting extension 25 and designed to t within a socket in a turret 28 or other appropriate feature of a machine suitable for threading or similar operations.

' The Chaser-carrying member 21 is of ring-like form and has a hollow stepped interior providbearing upon they periphery of the flange 26 of the mounting-member 20, and an internal cylindrical bearing-surface 30 bearing upon the periphery of the bearing-extension 25 of the said mounting-member 20. The bearing-surfaces 29 and 30 just referred to provide for the axial movement of the Chaser-carrying member 21 with respect to the mounting-member 20 for the purpose as will more fully hereinafter appear.

For the purpose of preventing relative rotary movement between the Chaser-carrying member 21 and the mounting-member 20 while permitting relative axial movement, a pair of guidepins 31--31 project forwardly from the forward face of the flange 26 of the said mounting-member from diametrically opposite points thereon into aligned rearwardly-facing sockets 32-32 formed in the said Chaser-carrying member 21, as clearly shown in Fig. 9, for instance. The Chaser-carrying member 21 is normally held at the limit of its rearward movement with respect to the mounting-member 20 by a pair of complementary helical springs 33-33 located in longitudinal bores 34-34 extending through the flange 26 of the said mounting-member and bearing at their rear ends against the undersides respectively of the heads 35-35 of a pair of complementary screws 36-36 threaded into suitable internally-threaded sockets 3'7-37 formed at diametrically opposite points in the Chaser-carrying member 21, as clearly shown in Figs. 3 to 5 inclusive. The forward ends of the springs 33-33 bear against the respective rear faces of bushings 38-38 mounted respectively in the rear ends of the said bores 34-34.

At its forward end, the Chaser-carrying member is formed with an axial passage 39 leading rearwardly from its forward face into its hollow interior and from which four (more or less) radial grooves 40 extend outwardly to its periphery. Installed in each of the grooves 40 with capacity for radial movement therein is a chasermounting slide 41 having secured to its outer face a so-called circular chaser 42. Each of the Chaser-mounting slides 41 is urged radially outwardly by a helical spring 43 housed therein, as shown in Fig. '7.

Each Chaser-mounting slide 41 is formed upon its outer face with a sloping cam-surface 44 coacting with a similarly-sloped cam-surface 45 (one of which is provided for each slide) formed upon the inner face of the forward end of the ring-like Chaser-operating member 22 before referred to. The said Chaser-operating member bears upon the periphery of the Chaser-carrying member 21 and has axial movement with respect thereto, for the purpose of controlling the radial movement of the Chaser-mounting slides 41 and hence of the chasers 42.

Threaded into the rear end of the said chaseroperating member 22 and forming under all normal conditions a unit therewith is the adjustingring 24 before referred to, which rides, in turn, upon the periphery of the Chaser-carrying member 21, as is clearly apparent in Figs. 3 to 5 inclusive. The said adjusting-ring 24 is formed internally with an annular groove 46, the forward wall of which forms an annular lockingabutment 47 which is engaged by the segmental locking-member 23 before referred to.

Normally urging the chaser-operating member 22 rearwardly, and hence also the adjustingring 24, is a pair of hollow spring-plungers 48--48 corresponding to each other and respectively located diametrically opposite each other, as indicated in Fig. 2, and each of which bears at its rear end against the forward edge of the adjusting-ring 24, as clearly shown in Fig. 8. Each of the said plungers reciprocates in a bore 49 in the Chaser-carrying member 21 and is urged rearwardly by a spring 50 extending into its hollow interior.

To prevent the Chaser-operating member 22 from turning with respect to the Chaser-carrying member 21 and to limit the same to axial movement, the inner face of the said chaser-operating member is provided with a keyway 51 receiving the outwardly-projecting portion of a key 52 seated in the periphery of the chaser-carrying member 21 near the forward end thereof, as shown in Figs. 3 to 5 inclusive.

For the purpose of limiting the rearward travel of the chaseroperating member 22 with respect to the Chaser-carrying member 21 under the urge of the springs Bil-50, the periphery of the said Chaser-carrying member is formed with an elongated socket 53 receiving the inwardly-projecting end of a stop-plunger 54 mounted for reciprocat ing movement in a bushing 55 mounted in and extending outwardly from the periphery of the said Chaser-operating member 22. The said plunger is provided at its outer end with a knurled fingerbutton 56 for retracting its inner end out of the groove 53 against the counter-urge of a helical spring 57, as clearly shown in Fig. 7.

For the purpose of moving the Chaser-operating member 22 axially forwardly with respect to the Chaser-carrying member 21 to thus cam the Chaser-mounting slides 41 radially inwardly to thus move the chasers 42 inwardly into their cutting positions, a hand-lever 58 is pivotally mounted by means of a pin 59 in the said chaseroperating member. The spherically-contoured inner end 60 of the said lever extends inwardly into a socket 61 formed in the Chaser-carrying member 21.

The segmental locking-member 23 reciprocates substantially radially in a transverse groove 62 formed in the Chaser-carrying member 21 and intersecting both the interior and exterior surfaces thereof. The said locking-member is urged radially outwardly for engagement with the locking-abutment 47 by a pair of complementary springs 63-63 (Fig. 6) respectively seated inI sockets 64-64 formed in the inner face of the said locking-member and bearing at their inner ends against the bottom of the transverse groove 62. The said locking-member 23 is formed with a clearance-passage 65 through which extends the adjacent one of the screws 35, which latter serves to limit the outward travel of the lockingmember 23. The said locking-member 23 is formed in its forward face with an oblique segmental cut 66, the inner rear wall of which forms a forwardly-and-inwardly-inclined segmental cam-surface 6'? having sliding engagement with a similarly-sloped cam-surface 68 forming the forward wall of a transverse groove 69 extending transversely across the periphery of the bearingextension 25 of the mounting-member 20, as clearly shown in Figs. 3, 4, 5, 11 and 12.

Instead of employing circular chasers 42 carried by the slides 41, other forms of chasers or..30

appropriate cutters may be used such, for instance, as the bar-like chasers shown in the prior patent, No. 1,643,832, before referred to, and which are directly mounted for radial movement in the Chaser-carrying member.

Let it be presumed that the parts are in the positions in which they are shown in Fig. 3, in which the chasers 42 have been moved radially inward into their cutting positions. A rod or other work 70 represented by broken lines in Figs. 3 to 5 inclusive may now be engaged with the "-f chasers and rotated with respect thereto, so as to be provided with an external thread. Either the work or the die-head, or both, is, during this operation, moved axially one toward the other, and when the desired length of thread has been cut carrying member 21 forwardly with respect to the l 1GO mounting-member 20 against the tension of the springs 33-33.

The relative forward axial movement of the Chaser-carrying member with respect to the mounting-member 20, as just above described, will cause the bodily forward movement of the locking-member 23, inasmuch as the latter is carried by the said Chaser-carrying member. The bodily forward movement of the said lockingmember occasioned as just described will result in causing the cam-surface 67 of the said lockingmember to ride-up, so to speak, the cam-surface 68 of the mounting member until such time as the said locking-member is drawn inwardly suiciently to clear the annular locking-abutment 47 in the adjusting-ring 24. This position of the parts is clearly shown in Fig. 4, which shows the locking-member 23 at the instant of its disengagement With the said locking-abutment 47.

As soon as the forward face of the lockingmember 23 has been withdrawn out of engagement with the locking-abutment 4'7, the springs 50-50 will assert themselves and snap the chaseroperating member 22 and the adjusting ring 24 rearwardly until the inner end of the stop-plunger 54 engages the rear wall of the socket 53 in the Chaser-carrying member 21. As the said chaseroperating member 22 is moved rearwardly, it will thereby, in turn, permit the springs 43 to retire their respective Chaser-mounting slides 41, and hence the chasers 42, radially outward, out of engagement with the work 70.

The disengagement of the chasers from the work as just above described Will then permit the springs 33-33 to assert themselves and restore the Chaser-carrying member and the parts carried thereby to its normal rearward position, as shown in Fig. 5.

The die-head may now be restored to the position in which it is shown in Fig. 3, by forcing the projecting outer end of the lever 58 forwardly, which will move the Chaser-operating member 22 forwardly with respect to the Chaser-carrying member and thus force the Chaser-mounting slides 41 radially inward and similarly move the chasers 42 inwardly into their cutting positions, preparatory to another cycle of operation.

By so constructing and arranging the parts that the locking-member 23 is virtually carried by the Chaser-carrying member 21 and is cammed inwardly into its unlocking position by direct engagement with suitable cam-surfaces carried by the mounting-member 20, I secure a degree of sensitiveness in the unlocking action much superior to that which was obtained by means of the mechanism illustrated in prior Patent No. 1,643,832 before referred to. In the latter patent, it will be noted that the locking-member is carried by the mounting-member and moves bodily in an inclined path under the urge of the chasercarrying member. By means of the present invention, the sensitiveness of the die-head has been so increased that thread forms of very ne pitch may be formed in relatively soft metal Without danger of the stripping of such threads when the same are called upon to effect the unlocking of the die-head as before described.

The invention may be carried out in other specific ways than that herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiment is therefore to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency member and provided with a locking-abutment;

and a locking-member mounted in the lockingmember-receiving passage of the said chasercarrying member and provided with an inclined cam-surface coacting with the inclined cam-surface of the said telescoping portion of the said mounting-member for being moved inwardly out of engagement with the locking-abutment in the said Chaser-operating member by a relative axial movement between the said Chaser-carrying member and the said mounting-member.

2. A self-opening die-head comprising: a ringlike Chaser-carrying member provided with a radial locking-member-receiving passage extending substantially-radially therethrough from its inner to its outer peripheries; a mounting-member having a portion telescopically tting within the said Chaser-carrying member with respect to which it is axially movable and provided in the said portion with an inclined cam-surface; a Chaser-operating member telescopically fitting over and axially movable with respect to the said Chaser-carrying member and provided with a locking-abutment; and a locking-member mounted in the radial locking-member-receiving passage of the said Chaser-carrying member and provided with an inclined cam-surface coacting with the inclined cam-surface of the said telescoping portion of the said mounting-member for being moved radially inwardly out of engagement with the locking-abutment in the said chaseroperating member by a relative axial movement between the said Chaser-carrying member and the said mounting-member.

3. A. self-opening die-head comprising: a ringlike Chaser-carrying member provided with a transverse substantially-radial passage intersecting both its inner and outer peripheries; a mounting-member having a portion telescopically fitting within and having relative axial movement with respect to the said Chaser-carrying member and formed in the said portion with a forwardlyand-inwardly-inclined cam-surface; a ring-like Chaser-operating member fitting over and having relative axial movement with respect to the said chaser-carrying member and provided with a locking-abutment; a locking-member mounted in and slidable substantially radially in the radial passage in the said Chaser-mounting member and provided with a locking-surface engageable with the locking-abutment of the said chaser-operating member and also provided with a forwardly-andinwardly-inclined cam-surface having sliding engagement with the cam-surface oi the said telescoping portion of the said mounting-member for being moved axially inwardly by a relative axial movement between the said Chaser-carrying member and the said mounting-member.

4. A self-opening die-head comprising: a ringlike Chaser-carrying member provided with a transverse substantially-radial passage interthe radial passage in the said chaser-carrying member and provided with a locking-surface engageable with the locking-abutment of the said Chaser-operating member and also provided in its forward face with a V-shaped recess having an inner Wall engageable with the cam-surface of the said telescoping portion of the said mountingmember and inclined forwardly and inwardly to substantially correspond to the slope of the said cam-surface.

ALBERT F. BREITENSTEIN. 

